1. Field of the Invention
The present invention relates to an apparatus and process for making and sealing a cap and body assembly. More particularly, the present invention relates to a process wherein the cap and body assembly is molded, moved to a capping device and then sealed by closing the cap while the plastic of the body and cap has not fully set.
2. Description of Related Art
Leak proof plastic bodies of the type to which the present invention relates are generally injection-molded plastic bodies that have plastic caps adapted to seal the body closed with a substantially hermetic seal. Such bodies are for example, the vials used to collect samples in the dairy industry or other containers having caps. The caps may or may not be integrally connected to the bodies.
In the past such sealed bodies have been made by molding the bodies and caps in a first process and then sterilizing and sealing the caps onto the bodies in a separate process. In order to sterilize the interior of the bodies and to seal the caps onto the bodies, it has been known to heat and seal the caps and bodies under aseptic conditions.
U.S. Pat. No. 4,783,056 discloses a method for accomplishing sealing of a cap onto a vial including a mold with several moving parts in which the vial may be molded and sealed in the same apparatus. This method of forming and sealing an aseptic vial eliminates the additional step of sealing the vial under aseptic conditions because the sealing is done directly in the mold while the vial is still hot enough to maintain the necessary pliability and sterility of the vial. However, this method requires the use of a mold which has moving parts for closing and sealing the cap on the vial.
The present invention relates to a process for forming and sealing a cap and a body with a leak proof seal where the body is transferred from a mold where it is made to a capping device while the material of the body is still not fully set. The body is removed from the mold with a robotic arm and transferred to the capping device where the cap is placed on the body before the material of the cap and body has fully set to establish a leak proof seal between the body and cap.
More specifically, the invention relates to a process for forming a leak proof body and cap including steps of defining a mold cavity between a first mold part and a second mold part, injecting a molten material into the mold cavity thereby forming from the molten material a body and cap, and retracting the first mold part from the second mold part to separate the first mold part from the body and cap. Thereafter, engaging at least the body with a robotic arm and moving the body with the robotic arm into a capping device while the body and cap are at a temperature at which the material is not fully set. The body is then sealed by moving the cap into engagement with the body to form a leak proof seal.
In accordance with another aspect of the invention, an apparatus for forming an leak proof body with a cap includes a mold, robotic arm and a capping device. The mold has a first mold part, a second mold part and a mold cavity formed between the first and second mold parts. An injecting means for injects a molten material into the mold cavity to form a body and a cap. A retracting means retracts the first mold part from the second mold part to separate the first mold part from the body and cap. The robotic arm is configured to engage the body and cap, and move the body and cap from the mold to the capping device. The capping device seals the cap on the body while the body and cap are at a temperature at which the material of the body and cap is not fully set.